Complications of Abdominal Vagotomy in the Dog

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In the course of a study of Roux-Y drainage after hemigastrectomy and vagotomy in a canine model, unexpected complications were encountered. In our erst 25 specimens there occurred 3 symptomatic hiatal defects with herniated liver into the left pleural space. Respiratory compromise was the primary symptom of the herniation.The changes in oursurgical technique of vagotomy described belowsolved the problem. A literature search has revealed no speciec technique for vagotomy in the dog. The subdiaphragmatic hiatal anatomy of a dog is different than that of a human. A subdiaphragmatic vagotomy in humans is accomplished through an avascular plane in the hiatus, which is widely separated from the pleurae. We have found that the pleural cavity in dogs extends to the avascular plane of esophageal dissection. The anterior vagus is also different in the dogin that it consists of multiple branches lying between the peritoneum and esophagus, compared to a more discrete nerve trunk in humans. The hepatic anatomy in the dog is characterized by 4 lobes, 4 sublobes, and 2 processes, which are more mobile than the bilobate human liver.These smaller,mobile hepatic lobes in the dogs contributed to their tendency to herniate. We solved the problem and facilitated the dissection by deliberately entering the pleural spaces, easily dissecting the vagi, and repairing the pleurae by approximating the diaphragmatic muscles behind the esophagus. After exposing the esophageal hiatus, an incision is made in the peritoneum between the esophagus and each crus of the diaphragm. Blunt and sharp dissection is used at this point to mobilize the esophagus. It is at this point that the pleural spaces are entered. Pleural defects approximately 3 cm. in length are created. The esophagus is elevated and held using a Penrose drain. Once the pleural space has been entered the posterior vagus is easily identieed as a single trunk 4 mm. in diameter (Fig. 1). The posterior vagus is then doubly clamped and tied after excising a segment. Attention is next turned to the anterior vagal ebers. At this level, the anterior vagus exists as multiple branches (Fig. 2) in the peritoneum and areolar tissue (about 1.5 cm. to 2.0 cm. in width) anterior to the esophagus. This tissue is isolated. Again a segment is excised with each free edge being tied. At this point the esophagus is inspected for any remaining vagal ebers which are removed if identieed.